Often called NGC 281, this bright nebula located far below the galactic plane is also nicknamed the Pac Man nebula by amateur astronomers after a 1980s-era video game character. IC 1590
, the star cluster at the heart of the nebula, is about 3.5 million years old. The core of the star cluster IC 1590 is the trapezium system HD 5005
, which ionises NGC 281 and contains an O5.5 class star.
The distance to NGC 281 has been accurately measured via radio parallax as 2820 +/- 240 pc.
It is highly unusual to find such a prominent nebula so far below the galactic plane and there is some evidence that it is on the edge of a superbubble that has blown out of the galactic plane, perhaps because of multiple supernova explosions.
This nebula is often the subject of astrophotographers and there are many beautiful images of it on the Internet. One interesting false-colour version was Astronomy Picture of the Day
You can see a view of this nebula in infrared taken by the WISE satellite here
The core of the star cluster IC 1590 is the trapezium system HD 5005, which ionises the nebula.[1
Recent study. [2
Evidence of superbubble blowout. [3
IC 1590, the star cluster at the heart of the nebula, is about 3.5 million years old. [4
1. ^ Henning, Th., Martin, K., Reimann, H.-G., et al. (1994). "Multi-wavelength
study of NGC 281 A", Astronomy and Astrophysics, Vol. 288, 282-292.
2. ^ Lee, Youngung & Jung, Jae-Hoon (2003). "A molecular cloud complex above
the galactic plane.. I. Extended CO observations of the NGC 281 region",
New Astronomy, Vol. 8, 191-207. [2003NewA....8..191L]
3. ^ Sato, Mayumi, Hirota, Tomoya, Honma, Mareki, et al. (2007). "Absolute
Proper Motions of H2OMasers Away from the Galactic Plane Measured with VERA
in the "Superbubble" Region NGC 281", Publications of the Astronomical
Society of Japan, Vol. 59, 743. [2007PASJ...59..743S]
4. ^ Guetter, Harry H. & Turner, David G. (1997). "IC 1590, A Young Cluster
Embedded in the Nebulosity of NGC 281", The Astronomical Journal, Vol.
113, 2116. [1997AJ....113.2116G]